The invention relates to a molding installation for the production of bipartite, boxless foundry molds, consisting of a molding machine with a molding station wherein the cope and the drag are simultaneously shaped above a bilateral pattern arranged therebetween and thereafter are lifted off from the pattern in the upward and downward directions, respectively, and of a conveying means by which the cope and the drag are conveyed along a closed path from the molding station of a joining and stripping station where the cope and drag are recombined and then are removed together from the complete foundry mold, and the empty molding boxes are returned to the molding station, while the boxless foundry mold is transferred to a casting line wherein, between the molding station and the joining and stripping station, there is provided at least one processing station for conducting finishing work on at least one of the two molds, for example, for the insertion of cores.
The boxless molding process has the advantage that only a low number of molding boxes is required within the molding installation so that the initial investment costs are correspondingly low. In this connection, especially in large series-type operations, those molding machines proved themselves advantageous, by means of which the cope and the drag are simultaneously shaped. In molding machines of this type, the foundry sand is injected in general from above into the cope and from below into the drag and is thereby compacted, optionally with the aid of an additional pressing step. Then, the cope and drag are lifted off from the pattern disposed therebetween and, optionally after conducting finishing work on both or on one of the two molding boxes, joined together. Thereafter, the molding boxes are closed again with the interposition of the pattern for the production of a new foundry mold. As compared to the individual manufacture of cope and drag, turning processes for one of the two molding boxes are eliminated.
Since in these molding machines the cope and the drag are directly superposed, finishing work on one of the molding boxes can be effected in this position only with difficulties. In a conventional arrangement, the drag, which normally is the only one requiring a finishing step, for example, due to the necessity of inserting cores, is positioned on a turntable with two or three rotary positions. One position pertains to the molding station wherein the pattern is arranged above the drag and the cope is disposed thereabove. After the shaping step, the drag is turned into a position located outside of the molding station and is provided with cores. Thereafter, the drag again enters the molding station from which the pattern has first been removed. In the molding station, the cope is added, the cope and drag are removed, the boxless mold is transferred to the casting line, and the pattern is reintroduced, whereupon a new shaping step takes place. The output of molds is limited and is determined by the work at the coring-up station which generally is conducted manually. Also, the accumulation of working operations within a minimum amount of space is disadvantageous.
In other conventional molding installations (DOS Nos. 2,303,561; 2,721,874), four copes and four drags are arranged on respectively one wheel spider or on respectively one rotary disk passing in succession through various processing stations in four rotary steps. In the molding station, the molding boxes closed over the pattern are filled with foundry sand, the latter is compacted, and then the molding boxes are lifted off the pattern in the upward and downward directions, respectively. After a revolution increment, both molding boxes reach a coring-up station (drag) and, after a further revolution increment, the joining and stripping station wherein the cope and drag are joined and then stripped together off the mold. In a subsequent revolution increment, the empty molding boxes, on the one hand, and the foundry mold, on the other hand, reach a dispatch station wherein the foundry mold is pushed onto a casting line. In the last revolution increment, finally, the two empty molding boxes reenter the molding station.
Although a higher efficiency can be attained with these molding installations, this is achieved at the cost of considerable disadvantages. Since the rotary disks or wheel spiders serving as the conveying means must accommodate in each case four molding boxes simultaneously and, at the same time, must exhibit the necessary moving means for the molding boxes, structural masses result which must be constantly accelerated or decelerated. Furthermore, the drag is accessible only with difficulties at the processing station, since the cope is disposed directly above the drag. Such a molding installation furthermore permits only a limited number of processing stations, normally even only a single processing station, since otherwise the structural masses become too large.
Starting with this prior art, indicated in the foregoing, the invention is based on the object of constructing the molding installation in such a way that it is possible, while avoiding the accumulation of operations within a narrow space, to provide several processing stations, optionally as many processing stations as desired, without thereby reducing the output of molds.
To attain this object, the invention proposes, in place of a rotating system, to equip the conveying means with linear conveying lanes which are superimposed at least along part of their lengths, encompass the molding station and the joining and stripping station in this zone, and of which the upper conveying lane receives the copes, the lower conveying lane receives the drags, and at least the lower conveying lane can be extended by the number of required processing stations.
By means of the molding installation of this invention, a linear conveying means with two conveying paths is suggested instead of a rotating conveying system, which conveying paths are either completely or partially superimposed. In this connection, the arrangement can be such that, at least at the processing station, the cope and the drag (optionally at different heights) are disposed so that they separate from each other and are positioned side-by-side, so that one of the molding boxes (usually the drag) is readily accessible for finishing work. The drive forces of the conveying means can be lower than in the prior art, since the necessary carrying devices and moving means for the molding boxes need not be carried along. The masses to be accelerated and decelerated are less. Also, such an installation can be adapted more readily to existing space conditions, and the processing stations can be distributed so that the finishing operations can be effected unhindered. Finally, the installation permits not only an adaptation to existing requirements, but can also be subsequently altered at any time.
According to one embodiment of the invention, the two superimposed conveying lanes are conducted in a rectangular path and exhibit a linear section comprising the molding station, a readiness station for an empty pair of molding boxes arranged upstream thereof in the conveying direction, and a transfer station arranged therebehind, while the oppositely located linear section exhibits the joining and stripping station, in front thereof the processing station(s), and therebehind a transfer station, the two sections being joined by transverse conveyors.
This arrangement makes it possible to provide an arbitrary number of processing stations for the drag between the transfer station of the first section and the joining and stripping station of the second section, wherein this drag in certain cases will pass through a longer conveying distance than the cope.
A simple variation of this embodiment for only one processing station is distinguished in that the upper and lower conveying lanes exhibit an identical number of stations, and the transfer station of the first section and the processing station of the second section are directly connected by a transverse conveyor.
Another version of the previously described embodiment which is advantageous, in particular, if the drag must pass through more than one processing station is distinguished according to the invention by the feature that the lower conveying path between the transfer station of the first section and the joining and stripping station of the second section is longer by at least the number of processing stations provided, whereas the upper conveying lane connects this transfer station directly with the station located immediately behind the last processing station.
In this version, therefore, the drag passes along a conveying path which is longer by the number of processing stations as compared to the path traveled by the cope, which latter, in turn, is returned along the shortest possible route to the drag associated therewith. It can readily be seen that this version permits any desired number of processing stations with unrestricted access.
To obtain a maximally compact installation in connection with this version, the provision is suitably made to arrange the processing stations so that they are distributed along the mutually opposing sections of the lower conveying lane exhibiting the molding station, on the one hand, and the joining and stripping station, on the other hand, Here the provision is futhermore made that the transverse conveyor connecting these two sections and the transverse conveyor connecting the shorter sections of the upper conveying lane, just as the two transverse conveyors connecting the transfer station on the second section with the readiness station on the first section, are controlled synchronously. In this way, each time a drag is transferred from one section to the other section, a cope is also simultaneously transferred from one section to the other section and, on the other end of the conveying lanes, at the same time an empty pair of molding boxes is brought into the readiness position.
By means of the aforedescribed solution to the problem with which this invention is concerned, it is furthermore possible to construct the molding installation in such a way that the cope as well as the drag can pass through several processing stations. For this purpose, an embodiment is specifically provided which is characterized by the fact that the lower conveying lane is extended in a closed rectangle and comprises a linear section encompassing the molding station, the joining and stripping station, and the readiness station, and an oppositely located, linear second section encompassing the processing stations, both sections being connected by transverse conveyors. This embodiment is furthermore characterized in that the upper conveying lane extends only along the first section, and directly before each transverse conveyor in the travel direction a turning device is arranged, one of these turning devices removing the shaped copes from the upper conveying lane, turning same, and transferring same to the opposed, second section of the lower conveying lane between, respectively, one drag, while the second turning device takes off the cope behind the processing stations from the lower conveying lane, turns same back to the upper conveying lane, and correlates this cope with the drag located thereat. In this connection, finally, the provision is made that the cope and the drag are advanced on the section of the lower conveying lane exhibiting the processing stations upon each conveying step by two positions, while they advance on the opposite section, just as the drags on the transverse conveyors, only by one position upon each conveying increment.
Thus, on one linear section of the two conveying lanes, encompassing the molding station, the cope and the drag are respectively superimposed, while they are arranged side-by-side on the opposite section with the processing stations. Thereby finishing work can be conducted on copes and drags. Since at the end of this section each second molding box, namely respectively the cope, is taken off and turned back to the opposite section, it is ensured by the dual step executed with each conveying increment that the entire molding installation operates in the rhythm of the molding machine, i.e. the mold output is determined exclusively by the efficiency of the molding machine. Here too, it can be readily seen that any desired number of processing stations can be provided, without thereby reducing the output of molds.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.